The present invention relates in general to clamping frames for holding multipart workpieces together while they are assembled, particularly on an assembly line, and in particular to a new and useful mechanisms for holding workpieces of different configurations wherein a plurality of clamping frames can be brought individually from a standby position into a working position for holding the pieces of a workpiece together.
Such clamping frames are employed particularly in the assembly line manafacture of car bodies. They are used to receive and centrically clamp blank parts of the car body such as the sides, bottom and top, which are only temporarily held together and are mostly fed in along the assembly line, in order to make possible an automatic welding of the body.
It is known from German OS No. 28 10 822, to assemble and weld in a common assembly or transfer line, blank car bodies of two different designs. For this purpose, a corresponding set of clamping frames is provided for either of the designs, which is then brought into working position by means of a programmed control. The other set of frames which is not employed in the operation, must remain in a standby position so as not to hinder assembly operations.
In this prior art method, the standby positions are provided ahead of and behind the working position, considered in the transfer line direction. This has the disadvantage that consecutive working positions must be spaced from each other by at least the length of the set of clamping frames. In comparison with rigidly connected transfer lines, which, on the other hand, of course, allow an assemblage of bodies of uniform design only, such an arrangement requires much more space.